Boiler

ABSTRACT

A boiler has two main concentric cylinders defining a water jacket between them. A smaller cylinder, located inside the inner of the two concentric cylinders in the upper half thereof, contains a plurality of tubes each having turbulator means. Two more water-filled cylinders, still smaller in diameter, are connected to the water jacket and are arranged on both sides of the smaller cylinder in the upper half of the inner cylinder, in contact therewith and spaced from said inner cylinder by narrow passages. The combustion chamber is in the inner main cylinder, below said smaller cylinder and water-filled cylinders and bounded partly thereby. A convection chamber in the inner main cylinder is connected to said combustion chamber by the narrow passages. The tubes have an entrance end spaced back from the front closure of the main cylinders, so that the combustion gases from the combustion chamber first pass into the convection chamber and flow toward the front closure and then enter and flow through the tubes, heating the water in the water jacket and in the water-filled cylinders. As a result, the flue gases produced by the combustion, return without any considerable pressure loss and at the same time decrease their temperature by transferring their enthalphy through convection, and the smaller cylinder and water-filled cylinders protect the flue gases produced by the combustion from the radiation effect of the combustion flame.

United States Patent 1 0zaltay [4 1 Dec. 25, 1973 BOILER [76] Inventor: H. Cevdet jzaltay, Kucukesat Caddesi, 55/13, Ankara, Turkey [22] Filed: Jan. 15, 1973 [21] Appl. No.: 323,862

[30] Foreign Application Priority Data Jan. 19, 1972 Turkey 003222 [52] U.S. Cl 122/149, 122/267, 122/269 [51] Int. Cl. F22b 25/00 [58] Field of Search 122/137, 140, 141, 122/149, 267, 268, 269

[56] References Cited UNITED STATES PATENTS 762,893 6/1904 Farrell et al. 122/269 889,388 6/1908 Moran 122/268 2,062,033 11/1936 Leuvelink t 122/268 X 2,080,404 5/1937 Hunter et al 122/149 2,207,162 7/1940 Ross 122/267 2,892,451 6/1959 Brown, Jr. et al. 122/149 Primary Examiner-Kenneth W. Sprague Attorney-Owen, Wickersham & Erickson [57] ABSTRACT A boiler hastwo main concentric cylinders defining a water jacket between them. A smaller cylinder, located inside the inner of the two concentric cylinders in the upper half thereof, contains a plurality of tubes each having turbulator means. Two more water-filled cylinders, still smaller in diameter, are connected to the water jacket and are arranged on both sides of the smaller cylinder in the upper half of the inner cylinder, in contact therewith and spaced from said inner cylinder by narrow passages. The combustion chamber is in the inner main cylinder, below said smaller cylinder and water-filled cylinders and bounded partly thereby. A convection chamber in the inner main cylinder is connected to said combustion chamber by the narrow passages. The tubes have an entrance end spaced back from the front closure of the main cylinders, so that the combustion gases from the combustion chamber first pass into the convection chamber and flow toward the front closure and then enter and flow through the tubes, heating the water in the water jacket and in the water-filled cylinders. As a result, the flue gases produced by the combustion, return without any considerable pressure loss and at the same time decrease their temperature by transferring their enthalphy through convection, and the smaller cylinder and water-filled cylinders protect the flue gases produced by the combustion from the radiation effect of 5 Claims, 2 Drawing Figures BOILER BACKGROUND OF THE INVENTION This invention relates to oil and gas-operating boilers for central heating and steam generating.

Over-pressure or super-pressure combustion in boilers has the advantages that the boilers may be made smaller with less material without their efficiency being decreased or their life shortened, and combustion is independent of the draught so that chimneys with smaller sections can be built.

The disadvantages of such boilers are that overpressure burners are costlier, they operate with greater noise and at higher pressures, they cause flame vibrations which result in further noise in the installation, the initial ignition of the burner is more difficult, and the burner is more troublesome in maintenance.

SUMMARY OF THE INVENTION One of the objects of the present invention is to make good use of the advantages of over-pressure combustion and at the same time reduce its disadvantages.

The main advantage of over-pressure combustion is its ability to reduce the dimensions and the cost of boilers. Due to the over-pressure combustion it is possible to reduce considerably the convective surfaces of the boilers, because by over-pressure the flue gas velocities are increased and so are the heat transfer ratios. Although it is possible also to reduce the radiation surfaces by over-pressure combustion, this reduction is not of great use because it is comparatively small, it increases the heat transfer ratio, and it disturbs the formation of a full flame. Therefore, the reduction of size of the boiler is basically the reduction of convective surfaces and, as mentioned above, this can be done because of the velocity of flue gases over these surfaces. To this end, there is a need for a pressure potential over these surfaces. If used in the combustion chamber, the pressure is not as functional, and it increases further the total inner resistance of the boiler.

In the combustion chamber the heat is mainly transferred through radiation. The gases leaving the chamber are under the radiation effect of the flame and therefore cannot be under a certain high temperature. If the convective area is directly connected with the combustion chamber, as is the case in most up-to-date boiler constructions, the gases enter this pass at a high temperature. In order to reduce this high entrance temperature down to an acceptable flue gas exit temperature in the last pass, the pressure potential needed is excessive. For this reason, the gases have to be freed of the radiation effect of the flame before entering the last flue gas pass.

BRIEF DESCRIPTION OF THE DRAWING The accompanying drawing shows, by way of exam- DESCRIPTION OF THE PREFERRED EMBODIMENT A boiler of this invention comprises two concentric cylinders 1 and 2, a smaller cylinder 3 containing a plurality of tubes 4 (e.g., seven tubes 4), and two more cylinders 5 and 5 arranged on opposite sides of the cylinder 3. All of the cylinders 3, 4, and 5 lie within the cylinder 2, and the space between the cylinders 1 and 2 is filled with water and forms a water jacket. The cylinders 5 and 5 are filled with water, as is the cylinder 3 outside the cylinder 7. The whole may be enclosed in a housing 17 having heat-insulating walls' In the lower portions of the cylinder 2, below the cylinders 3, 5, and 5' is a combustion chamber C, the burning fuel entering from a burner 16.

The gases leaving the combustion chamber C pass through narrow spaces 6 and 6 parallel to a flame shaft into first convection areas 7 and 7' and travel back toward the front (to the left in FIG. 1) without pressure loss toward the entrance of the seven tubes 4 through which they pass rearwardly, i.e., toward the right in FIG. 1. Turbulators 11, which may be steel bars coiled into helices, are disposed in the tubes 4 and the main part of the inner resistance of the boiler is in the tubes 4. In other words, the main part of the pressure is necessary in the pass through the tubes 4.

The flue gases leave the radiation area of the combustion chamber C through the narrow spaces 6 and 6' freed from the radiation effect of the flame and, subject to convective heat transfer in the convection areas 7 and 7 enter the tubes 4 at lower temperatures. At this end it is possible to push out the flue gases at a small pressure loss and to obtain the lowest permissible flue gas exit temperatures out of the said seven turbulating tubes 4 in the last pass around 200 C. Since the entrance temperature into the tubes 4 is withinvacceptable limits the t-urbulator 11 need not be made of special heat-resistant material.

The water being heated or boiled enters at an inlet 8,

flows out the cylinder 3 (outside the tubes 7), into the cylinders 5 and 5, into the water jacket 9 between the cylinders l and 2, and out through an outlet 10.

The invention enables the manufacture of small boilers which make full use of the main advantage of overpressure combustion with an over-pressure that may be provided by normal burners without special measures, thus avoiding to a large degree the disadvantages of a full over-pressure combustion.

The combustion chamber surface 12 is shown by the dotted area in FIG. 2. In the combustion chamber C, the areas 13 and 14, which are directly in the path of the flame, are of refractory brick. An explosion flap 15 may be provided for safety. A burner 16 provides the flame. The whole may be housed in refractory walls 17. As can be seen, the combustion chamber C is bordered by the stack cylinder 3 and the cylinders 5 and 5'. The dotted surfaces of these cylinders 3, 5, and 5' are almost equal in area to the undotted part of the inner cylinder 2, so that the surface of the combustion chamber C is almost as large as the inner surface of the cylinder 2. Therefore, compared with the outer dimensions of the boiler, the combustion chamber C is extremely large. This enables the manufacture of small boilers as well, due to the large size of the combustion chamber C, as smaller heat transfer ratios (kcallhlm and also smaller heat transfer ratio difference in different parts of the boiler, which is decisive for the longer life of this construction.

The flue gases arrive at and enter the seven tubes 4 last after passing through'the-spaces 7 and 7 of the second pass, transferring convective heat while free from the radiation effect of the flame, at a moderate temperature without pressure loss. The flue gas temperature is further reduced down to a permissible limit in the turbulators 11 mounted in the seven tubes 4 through convective heat transfer using fully the necessary moderate pressure potential.

The flue gases, produced by the combustion, return without any considerable pressure loss and at the same timedecrease their temperature by transferring their enthalphy through convection, and the tubes containing the turbulators are utilized to obtain the most favorable stack gas temperature with the most favorable dimensions and pressure loss.

With this arrangement, full use of the advantages of over-pressure combustion is reached; that is, a small, highly efficient boiler of a very simple construction yet operable with normal burners; in other words, avoiding the disadvantage of over-pressure combustion.

To those skilled in the art to which this invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the spirit and scope of the invention. The disclosures and the description herein are purely illustrative and are not intended to be in any sense limiting.

I claim:

1. A warm heater boiler comprising two main concentric cylinders defining a water jacket between them and front and rear closure means,

a smaller cylinder located inside the inner of the two concentric cylinders in the upper half thereof,

a plurality of tubes inside said smaller cylinder, each having turbulator means,

two more water-filled cylinders connected to said water jacket and to said smaller cylinder, for water flow therethrough and smaller in diameter than said smaller cylinder and arranged on both sides of the smaller cylinder in the upper half of said inner cylinder, in contact therewith and spaced from said inner cylinder by narrow passages,

a combustion chamber in said inner main cylinder below said smaller cylinder and said water-filled cylinders and bounded partly thereby, and

a convection chamber in said inner main cylinder and connected to said combustion chamber by said narrow passages,

said tubes having an entrance end spaced back from .the front closure of said main cylinders, so that the combustion gases from said combustion chamber first pass into said convection chamber and flow toward said front closure means and then enter and flow through said tubes, heating the water in said water jacket and in said water-filled cylinders,

so that the flue gases, produced by the combustion, return without any considerable pressure loss and at the same time decrease their temperature by transferring their enthalphy through convection,

the smaller cylinder and water-filled cylinders protecting the flue gases produced by the combustion from the radiation effect of the combustion flame.

2. A boiler as claimed in claim 1, comprising seven tubes, each containing turbulator means.

3. A boiler as claimed in claim 1 or 2, wherein the turbulator means are made of steel bars formed into helical coils.

4. The boiler of claim 1 wherein said smaller cylinder extends beyond the rear closure means of said rear closure means.

5. The boiler of claim 1 having a water inlet into said smaller cylinder and a water outlet from said water jacket. 

1. A warm heater boiler comprising two main concentric cylinders defining a water jacket between them and front and rear closure means, a smaller cylinder located inside the inner of the two concentric cylinders in the upper half thereof, a plurality of tubes inside said smaller cylinder, each having turbulator means, two more water-filled cylinders connected to said water jacket and to said smaller cylinder, for water flow therethrough and smaller in diameter than said smaller cylinder and arranged on both sides of the smaller cylinder in the upper half of said inner cylinder, in contact therewith and spaced from said inner cylinder by narrow passages, a combustion chamber in said inner main cylinder below said smaller cylinder and said water-filled cylinders and bounded partly thereby, and a convection chamber in said inner main cylinder and connected to said combustion chamber by said narrow passages, said tubes having an entrance end spaced back from the front closure of said main cylinders, so that the combustion gases from said combustion chamber first pass into said convection chamber and flow toward said front closure means and then enter and flow through said tubes, heating the water in said water jacket and in said water-filled cylinders, so that the flue gases, produced by the combustion, return without any considerable pressure loss and at the same time decrease their temperature by transferring their enthalphy through convection, the smaller cylinder and water-filled cylinders protecting the flue gases produced by the combustion from the radiation effect of the combustion flame.
 2. A boiler as claimed in claim 1, comprising seven tubes, each containing turbulator means.
 3. A boiler as claimed in claim 1 or 2, wherein the turbulator means are made of steel bars formed into helical coils.
 4. The boiler of claim 1 wherein said smaller cylinder extends beyond the rear clOsure means of said rear closure means.
 5. The boiler of claim 1 having a water inlet into said smaller cylinder and a water outlet from said water jacket. 